Recovery of metals.



UNITED STATES PATENT OFFICE.

ROBERT R. MAFFETT, OF-BAYONNE, NEW JERSEY, ASSIGNOR TO INTER- NATIONAL NICKEL COMPANY, A CORPORATION on NEW JERSEY.

RECOVERY OF METAL-8..

' Iv o. 833,722.

Specification of Letters Patent.

Patented Oct. 16, 1906.

Applicatioufiled December 2e,1905. Serial No. 293,218.'

' following is a specification.

In the art of reducing nickel-co .per ores it has been the practice to smelt t e matte containing sulfids of nickel, copper, and iron in a cupola-furnace, together with a charge of coke and sulfate of sodium, in the formof crude niter cake. The carbon of the coke reduces the sulfate of sodium to sulfid of sodium, and as this material when fused has a solvent action upon-the copper and iron sulfids contained in-the matte it will dissolve them to a considerable extent, so that when the molten contentsof the furnace are. tapped into settling-' ots the materials will stratify, the sul d of nickel, together with some sulfid of sodium, will settle to the bottom, and the sulfid of sodium, with the copper and iron sulfids'in solution, will float on the top. The mass when solidified is divided into topsvand bottoms, the tops containing sulfids' of copper, iron,

and sodium and the bottoms contalning sul-,

fid of nickel, together with such of the sulfids of copper: and iron as have not been taken up in solution in the sulfid of sodium. The bottoms are again charged into .the smelting-furnace with sulfate of sodium. and are resmelted a suflicient number of times to urify the, material to such an extent as to cave the nickel therein nearly free from copper, generally reducing the copper to less than one per cent. -After having thus been treated the bottoms are crushed and leached forthe purpose of removing the soluble portions of the sodium compound, and the product is dried and partially calcined and is then mixed with sodium chlorid and sodium sulfate and again calcined. The sodium chlorid and sodium sulfate react to produce chlorin gas, which converts the copper contained in the mass artially to the form of copper chlorid and tile remainder of the copper to copper sulfate, the nickel being converted largely to the'form of nickel oxid and partially to the form of nickel sulfate. The calcined product is then leached with water for the purpose of removing the soluble salts of the three meta1snamely, the copper chlomove the precipitate by rid and co per sulfate, sodium sulfate, and nickel sul ate. The residuum is then rewashed with dilute sulfuric acid, which removes the copper as a sulfate, but does not attack the nickel oxid. It has been the practice heretofore to precipitate the metals from these solutions by the addition. of sodium,

carbonate or sodium sulfid and thento reassing the liquor through filter presses, in w 'ch' operation the sodium compoun is lost;

I have discovered that the :o eration-of precipitating and filtering can e avoided and that the sodiumcompound which hitherto has been lost can be recovered by drawing off the liquor which results from the washing of the nickel copper compounds with water and sulfuric acid and which contains in solution sulfate of sodium and sulfates of copper and nickel and without the precipitation treatment which has been employed heretofore, introducing it into a vat,

where itis subjected to heat and is concentrated to the point of crystallization, at which the sodium-copper-nickel sulfate is recovered in the form of crystals. These crystals are taken from the vat and can be introduced directly into the smelting-furnace as a part of the charge of matte, coke, and sodium sulfate in the same manner in which niter cake has heretofore been introduced, and it has the'advantage not only of supplying the sulfate of sodium requisite for the smelting operation, but also of savifig the contained copper and nickel, which pass with the molten contents there recovered. My invention not only saves the sulfate of soda which has heretofore been lost as a result of the precipitation and filtering process, but it dispenses with the need of such pre-' cipitation and filtering and the subsequent smelting of the precipitate, and thus efiects a lar e economy 1n the recovery of the metals.

n the practice of the invention I prefer to use an evaporatin tank or pan having steamcoils therein, and ftake the solution of nickelcoppler sodium sulfate directly from theleac ing-vats and convey it in pi es to the tank, where it is heated and crystallized.

The apparatus and the steps of the process may be modified in various ways by those skilled in the art, since of the furnace into the settling-pots and are ICO' What I claim is' 1. In the art of separati matte containing sulfids of metals unequgfiy soluble in the fused sulfid of an alkaline metal, the method herein described which consists-in bringing the matte intocontact with such fused sulfid, converting the sulfids in part into sulfates, dissolving the sulfates associated with the sulfate of the alkaline metal, crystallizing the sulfates from such solution, and resmelting the same.

2. In the art of separatin matte containing sulfids of metals unequa' ly soluble in the fused sulfid of an alkaline metal, the method herein described which consists in bringing the matte into contact with such fused sulfid,

converting the sulfids in part into sulfates, dissolving the sulfates associated with the sulfate of the alkaline metal, crystallizin the sulfates'from such solution, and resme ting the samewith matte and'a reducing agent such as coke.

3. In the art of separating matte containing sulfids of nickel and copper, the method 1 herein described which consists in bringing l the matte into contact with the fused sulfid of an alkaline metal, eonvertin the sulfids in part into sulfates, dissolving t e sulfates associated with the sulfate of the alkaline metal, crystallizing the sulfates from such solution, and resmelting the same. 4. In the art of separating matte containing sulfids of nickel and copper, the method herein described which consists in bringing the matte into contact with the fused sulfid of'an alkaline metal, converting the sulfids in part into sulfates, dissolving the sulfates associated with the sulfate of the alkaline metal,'- crystallizing the sulfates from such solution, and resmelting the same with matte and a reducing agent such as coke.

In testimony whereof I have hereunto set my hand December 22, 1905.

ROBERT R. MAFFETT.

Witnesses:

THOMAS W. BAK WELL, GEORGE H. SONNEBORN. 

